The frog lived down in a well where there was all he had to live. One day, a softshelled turtle came by and told him about the sea. 'The sea? Hah! It's paradise in here. Nothing can be better than this well. Why don't you come down and share my joy?'

The turtle tried, and failed as the mouth of the well was too small. 'Why don't you go see the sea instead? During Yu the Great's reign, there was flooding for nine out of ten years, yet the sea barely grew an inch. During Tang of Shang's reign, droughts were experienced in seven out of eight years, yet the sea hardly shrank. Being unaffected by such disasters is the joy of living in the sea.'

Moral: Some ignorant people know nothing aside from their own world.[2]

The names the frog of the bottom of the well (井底之蛙) and glancing at the sky at the bottom of the well (坐井觀天) were not original titles by Chuang-tzu. The philosopher has given the fable no title. Such titles have been made up by others. In fact, the common interpretation of a frog in a well is incorrect. The word 井 had meant 'trap' back then.

Nowadays, both titles have been used as an idiom. The former means a person whose knowledge is so limited that he or she has no idea about anything aside from the world of their own; the latter means the action of being the kind of person mentioned above. Here is an example sentence using both idioms:

他經常在人家面前賣弄地理知識，其實，他只不過是個井底之蛙而已。我還是勸他別坐井觀天好了。

Which translates to:

He always shows off his geographical knowledge in front of others, yet he is simply an ignorant frog of the bottom of the well. I guess I'll advise him to stop glancing at the sky at the bottom of the well.